Studies On The Production Of Butene From ?-Valerolactone By Solid Acid

Butene is a basic chemical industrial feedstock,which can be used to produce fuel oil,plastics or other chemicals.Traditional methods of producing butene mainly rely on petroleum cracking.While,it is urgent to find a new way to produce butene due to the shortage of fossil energy.Recently,platform compounds extracted from biomass raw materials and further catalytic conversion of platform compounds to prepare chemicals and fuels have received extensive attention and development due to their extensive sources and low cost.It is worth noting that the platform molecule?-valerolactone can be produced by catalytic conversion of lignocellulose biomass,and further produce butene by decarboxylation reaction directly.In this research,?-valerolactone was used as raw material to produce butene by solid acid catalyzed.Firstly,high Al beta zeolite Nabeta-5 was synthesized by hydrothermal synthesis method and compared with commercial Hbeta-25,Hbeta-62 molecular sieve,commercial HZSM-5-38,HZSM-5-200,HY,and?-Al₂O₃ respectively for catalyzing of?-valerolactone decarboxylation to produce butene.The results showed that the catalytic activity of low Si/Al ratio beta zeolites was significantly better than that of other solid acids,while the catalytic activity of the self-made high alumina beta molecular sieve was higher than that of commercial beta molecular sieve.SEM?EDS?,XRD,NH₃-TPD,CO₂-TPD,Pyridine,FTIR,BET and other methods were used to characterize the tested solid acid catalysts,and the results show that,as a kind of crystalline material,the catalytic activity of high Al beta zeolite is higher than other materials due to its abundant Lewis acid sties and larger pore diameter?average pore diameter 0.62nm?.HZSM-5-5-38,HY and Nabeta-5 were selected for further research.The effects of catalyst content,reaction pressure,reaction time and reaction temperature on the reaction were investigated.The results showed that the optimum reaction conditions of HZSM-5-38as follows:catalyst content?17.5%?,the initial pressure?0Mpa?,reaction time?6h?,reaction temperature?340°C?;the optimum reaction conditions of HY as follows:catalyst content?15%?,the initial pressure?0Mpa?,reaction time?5h?,reaction temperature?320°C?;the optimum reaction conditions of Nabeta-5 as follows:catalyst content?10%?,the initial pressure?0Mpa?,reaction time?4.5h?,reaction temperature?300°C?.In the optimum reaction conditions,nearly 98%butene yield was obtained.Besides,the liquid products were analyzed by GC-MS.HZSM-5-5-38,HY and Nabeta-5 were modified by using different temperatures to calcinate on the purpose of changing the ratio of B/L acid.Then the modified catalysts were evaluated.The results showed that the calcination temperature had an effect on the total acid amounts and B/L ratio,while the total acid amounts and B/L ratio had an effect on the?-valerolactone decarboxylation.In general,more total acid amounts and higher ratio of L acid lead to more butene yield.When the total acid amounts remain unchanged,the lower the ratio of B/L is,the higher the butene is,which turned out directly that the activity of L acid was higher than B acid for?-valerolactone decarboxylation in crystalline material.